background and aims: avian influenza (ai) h9n2 subtype was first reported to infect turkeys in the united states in 1966 and has been panzootic in europe and asia. the impact of avian influenza caused by h9n2 viruses in iran is now significantly more severe than in previous years. methods: sequence analysis and phylogenetic study of the complete coding region polymerase a (pa) gene of h9n2 subt...

sequence analysis and phylogenetic study of hemagglutinin (ha) gene of h9n2 subtype of avian influenza virus isolates (outbreaks of 1998-2002) in tehran province (iran) were studied. two sets of forward and reverse primers in highly conserved regions, based on sequences of ha gene in genbank, were designed. pcr products of a 430-bp fragment of 16 isolates were sequenced and then were aligned wi...

Background and Aims: Avian Influenza (AI) H9N2 subtype was first reported to infect turkeys in the United States in 1966 and has been panzootic in Europe and Asia. The impact of avian influenza caused by H9N2 viruses in Iran is now significantly more severe than in previous years. Methods: Sequence analysis and phylogenetic study of the complete coding region Polymerase A (PA) gene of H9N2 subt...

Background and Aims: Avian Influenza (AI) H9N2 subtype was first reported to infect turkeys in the United States in 1966 and has been panzootic in Eurasia. In Iran, the H9N2 virus was first isolated from broiler chickens in 1998 in Ghazvin province and it is the most prevalent subtype of influenza virus in poultry industry in Iran at the present time. Materials and Methods: In this study, we se...

background and aims: avian influenza (ai) h9n2 subtype was first reported to infect turkeys in the united states in 1966 and has been panzootic in eurasia. in iran, the h9n2 virus was first isolated from broiler chickens in 1998 in ghazvin province and it is the most prevalent subtype of influenza virus in poultry industry in iran at the present time. materials and methods: in this study, we se...

Background and Aims: Since 1998, Iranian poultry industry has been affected by avian influenza (AI) virus, subtype H9N2. The association of high mortality and case report of H5N1 and H9N2 influenza virus in wild birds in recent years raised the suspicion of a possible new genetic modified AI virus. Methods: Partial nucleotide sequences and deduced amino acid of hemagglutinin (HA) genes of 4 H9...

BACKGROUND: Avian influenza (AI) viruses have been isolated from a wide diversity of free-living avian species representing several orders. Since 1998, H9N2 AI outbreaks have been one of the major problems in Iranian poultry industry. In 2006, H5N1 was reported in swans in the north of Iran first , but until now there has been no official report from commercial flocks in Iran. OBJECTIVES: The...

background: avian influenza (ai) viruses have been isolated from a wide diversity of free-living avian species representing several orders. since 1998, h9n2 ai outbreaks have been one of the major problems in iranian poultry industry. in 2006, h5n1 was reported in swans in the north of iran first , but until now there has been no official report from commercial flocks in iran. objectives: the a...

Background and Aims: Hemagglutinin (HA) protein of Avian Influenza (AI) plays an essential role in the virus pathogenicity. AI H9N2 subtype causes significant economic loss in broiler and layer in poultry farms in Iran. AI viruses have a great involvement in evolutionary changes at nucleotide and amino acid levels and vaccines could induce faster rates of such changes. Up-dated understanding of...

avian influenza is an important disease of poultry with the potential to cause major epidemics resulting in significant economic losses. the presence of avian influenza viruses (aiv) in chickens in iran has not been previously reported. an avian influenza outbreak in broiler, layer and breeder farms occurred during a very hot summer in july 1998. three aiv isolates designated as 101, 102 and 10...